adding closed captioning

I'm stumped. What is the difference between the sound option and the narrative option in the WSYIWYG editor on many pages? When is it advised to use each option?
I've been using narration mp3 files because I want the teacher narrative to auto run when the page loads. But I can not for the life of me figure out how to get the closed captioning to appear and user be able to toggle off/on. I must have this feature or else I can't get anyone to take my course. the New York state government department, the department of state is NOT going to approve my Xerte course for professional continuing education credit for the local municipal government's code enforcement officials without closed captioning. HELP?

Hi Rolaine
I think there are different things being asked here.
Can you confirm which page type you are using?
What is on the page with the narrative? An image and text, a video or something else?
When you say 'closed captioning', it sounds to me like something you would get if you upload a video to Youtube and the automatic CC appears that a user can toggle on or off. I don't believe this feature is automatic on a page type in Xerte.
The Synched Video page type and the Media Lesson are the only ones I can think of where you can make text appear at a set point with a video, but there is no feature to 'toggle on/off'.